Apparatus relating to preparation of worn tire casings for subsequent retreading or recapping operations have been widely developed and utilized in the retreading industry. The removal of lugs and rubber tread material from pneumatic tire casings is a well known procedure and is generally described by the term as "buffing". The term "buffing" has been used to identify the removal of old rubber from the tire carcass whether it is done by rough cutting wheels, texturizing wheels or finishing wheels.
The predominant manner of performing the operation of buffing is generally accomplished by abrading the periphery of the tire carcass with an abrading member which may be in the form of a rotating buffing wheel having rasp-like teeth on its peripheral surface, or a rotating buffing wheel having abrasive materials mounted thereon or a rotating buffing wheel having a plurality of circular chippers or cutting elements mounted thereon which chip away to remove the rubber tread material from the tire carcass of casing.
However, the primary problem encountered with buffing wheels having rasp-like teeth and coarse abrasives mounted thereon is that considerable heat is produced which results in the production of smoke and vapors during the buffing operation. Also, such buffing wheels produce large volumes of rubber dust particles which create a health hazard for workers in the area of operation. To overcome such difficulties, complex and expensive dust collecting and heat removal equipment are necessary to remove such contaminants from the work area. See for example, U.S. Pat. No. 3,711,909 which relates to rasp-like abrading wheels and U.S. Pat. Nos. 3,742,655 and 3,918,217 relating to abrading wheels having coarse abrasives or protrusions mounted to the periphery thereof.
It has also been suggested to mount hardened circular cutting inserts onto the rotating buffing wheel to thereby chip the tread material from the tire carcass to somehow overcome the problem of dust and heat that are prevelent with the rasp-like and abrading-type buffing wheels. Also, such devices, as shown in U.S. Pat. Nos. 3,888,145, 3,953,915 and 3,604,084, have been designed to provide a rotary detreading wheel having a plurality of circular cutting elements mounted therein which may be indexed and realigned to provide a new cutting edge when a portion of the cutting insert has become dulled during usage. Additionally, such devices have been designed to be bidirectional to provide a cutting action depending upon the rotation of the buffing wheel. Because, such devices are complex and expensive to manufacture, are difficult to maintain in operating conditions and often become clogged due to the removal of rubber from the buffed tire carcass, they have not found wide-spread application and adaption by the industry.